Influenza (abbreviated as flu) is an acute respiratory infectious disease caused by influenza virus. It is also a highly contagious and fast-spreading disease. The pathogen is influenza virus type A, B, and C, which is transmitted through droplets. The typical symptoms are usually as follows: sudden and rapid high fever, fatigue, body muscle aches and mild respiratory symptoms. The course of the disease is short and self-limiting. Middle-aged people and patients with chronic respiratory diseases or heart disease are prone to pneumonia. The most significant characteristics of influenza in epidemiology are: sudden outbreak, rapid spread, wide coverage, and certain seasonality (epidemics in northern my country generally occur in winter, while in the south they occur more in summer and winter). The recently popular influenza B is a type of influenza. Compared with the other two strains, it has little variation and is less likely to spread. In previous years, influenza B was mostly prevalent during the transition from spring to summer in May and June, and the symptoms were not obvious. This year, it broke out after the beginning of winter, which is a special phenomenon. Monitoring from November to December showed that 89% of influenza in Guangdong was influenza B. There are two strains of influenza B. The most common strain in the past was the Victoria strain, which is also the vaccine strain recommended by the World Health Organization this year. However, the influenza B strain that has appeared recently is the Yamagata strain, which is less common and is caused by the limited protection of the vaccine. Students should pay attention to personal hygiene, wash their hands frequently, open windows for ventilation, and go to the hospital for treatment in time if they find influenza symptoms such as fever, cough, and body aches.